A redundant array of independent disks (RAID), also known as a redundant array of inexpensive disks (RAID), is called a disk array for short. A principle of a RAID is to form a disk array group by combining a plurality of relatively inexpensive disks, so as to make performance reach or even exceed that of an expensive hard disk with a huge capacity; in addition, data security is improved in combination with a design of distributed data arrangement. According to a different version that is selected, a RAID, compared with a single disk, can not only enlarge a storage capacity but also enhance a data integration level and a data fault tolerance capability. In addition, for a computer, a disk array looks like an independent disk or a logical storage unit.
In an archiving scenario, many files need to be archived. Therefore, in the prior art, a RAID is generally used to store an archived file, and in order to improve data security, a RAID with a check function, for example, in a form of a RAID3, a RAID4, a RAID5, or a RAID6, is generally used to store an archived file. In the prior art, in order to improve a data access speed, a file is generally divided into several data blocks, and a plurality of data blocks belonging to one file, and a check block form a stripe of a RAID, and the stripe is written into a plurality of disks that forms the RAID. Because an archived file is less frequently accessed, in order to achieve an energy saving purpose, a disk in a storage system is generally in a dormant or power-off state after a file is archived. Only when an archived file needs to be accessed, a plurality of disks in which data blocks of the file are stored is wakened up or powered on, so as to read the file.